Creating an Inamorata Prognostication Engine, Part 3

In which Max constructs a jig to hold the brass panels for his Pedagogical and Phantasmagorical Inamorata Prognostication Engine.

I dream of having a proper workshop. If I had the money, I'd build something at the bottom of our back garden and equip it with all sorts of woodworking and metalworking tools. It would be wonderful to be able to spread out over multiple worktables and have things like circular saws and suchlike all set up and poised for action.

Oh well, I can but dream. In the real world, I have a little corner area in our garage where I store my rolling tool cabinets. Gina is a realtor, which means she works weekends. Thus, as soon as she drives off to work, I leap into action -- I wheel out my rolling tool cabinets -- set up a folding work table -- run an extension cable to power my drills and suchlike -- and start work on whatever project I'm currently playing with.

In the case of this past weekend, I decided to construct a jig to hold the brass panels for my Inamorata Prognostication Engine. In the fullness of time, these panels will be mounted in a beautiful wooden radio cabinet circa 1929. The point is that I don’t want to be working in this cabinet while I'm connecting everything together and prototyping things -- instead, I want easy access to the backs of all of the switches and knobs and meters.

My first step was to cut up some 3/4" plywood to make a base and two side supports as illustrated in the following image:

Next, I glued and nailed two 1/2" x 1/2" strips to each of the side supports as illustrated below. The gap between the strips is to accommodate a pressed board mockup of the radio cabinet's lower wooden panel at the bottom, and the larger brass panel at the top. Since the pressed board is a fraction of an inch wider than the brass panel, I used small pieces of pressed board to set the gap.

The following image shows the jig approaching its final stages. Now, I don’t know if you noticed in the earlier pictures, but the main (upper) brass panel is wider than the secondary (lower) brass panel. My life would have been so much simpler if they were the same width, but the difference is dictated by the way in which the two panels will eventually be housed in the radio cabinet. The problem is that, if left to its own devices, the lower brass panel -- which is to be located behind the pressed board -- would simply fall over.

I don’t want to go into two much detail here, but my solution is rather cunning. If you look at the image above, you'll see that in front of the pressed board at the bottom there is a 1/2" x 1/2" strip glued and nailed to the baseboard. There's a similar strip behind the pressed board, with an extra gap between the pressed board and the strip to accommodate the lower brass panel.

Also in the image above, you can see a bunch of clamps at the top of the pressed board. These are holding a sandwich of three pieces of wood together while the glue dries. It's probably easier to see what's going on using the following diagram, which shows a cross-sectional view (but without the side supports and their associated wooden strips).

Remember that the two 1/2" x 1/2" strips at the bottom are attached to the base -- they are not attached to the pressed board front panel, which is free to slide up and down in the grooves between the strips that are attached to the two side supports (again, the side panels and their associated strips are not shown in this image). At the top of the pressed board front panel we see the sandwich of three pieces of wood. These are the pieces that are being held together by the clamps in the previous image.

The end result is that I can slide the pressed board front panel up an inch or so, press the lower brass panel against the back, and then slide the pressed board front panel down, thereby locking the brass panel firmly in place. Next, I slide the upper brass panel down into the grooves in the side supports. The end result is as shown below.

I don’t know about you, but I think this is starting to look rather tasty. The next step is to temporarily attach the bezels, along with the buttons, switches, potentiometers, and analog meters, and to then start wiring everything up.

At the same time, I'm going to start experimenting with different techniques to age my brass so that it looks as though everything was fabricated more than 100 years ago. I've got a bunch of small brass offcuts to play with. Some of the techniques I've heard about thus far are to use salt and/or vinegar and/or baking in an oven. I've also heard that putting liquid ammonia in the bottom of a plastic container and then suspending the brass in the ensuing vapor can return good results. And someone told me that the Disney Imagineers use cow manure, but I'm not sure where to lay my hands on that (no pun intended).

I will of course be reporting further as things progress. In the meantime, I welcome any comments and/or questions and/or suggestions.

@Brian: You will have some on Friday (4/25) sometime between late morning and lunchtime.

Hi Brian, thanks so much for the horse and cow manure -- and please thank your sons Sam and Daniel for getting up early this morning to gather it for me (I get the impression that they's stopped asking questions when you say something like "Max" and "Cow Manure" in the same sentence LOL)

I will start my experiments first thing in the morning (after my realtor wife Gina has left for work LOL)

You will have some on Friday (4/25) sometime between late morning and lunchtime. We will bring a small amount of "material" from both cow and horse with the containers marked. The boys will be with me.

maybe you could work this one in (although I'm not sure how you could do the Steampunk look with it): Microview (an Arduino in a DIP package with OLED display - it looks really cute, but I'm passing because I don't have any immediate need for it and I have too many lonely dev kits).

@Brian: ...the field behind our house has cattle grazing on it. There is an endless supply of such material you speak of... :-)

Let me tell you where you can stick your cow manure .... in a plastic bag (just a couple of pounds -- say 5 pounds -- tripple wrapped) and bring it round to my office the next time you are passing -- i only need a small amount for my test pieces -- if this proves to be the best solution, I'll let you know how much more I need for the main panels.

The reason cow manure sounds like it might do the trick is that it's both acidic and salty and contains a lot of amonia -- all of which can be used to age brass.

@Max: I dream of having a proper workshop. If I had the money, I'd build something at the bottom of our back garden and equip it with all sorts of woodworking and metalworking tools. It would be wonderful to be able to spread out over multiple worktables and have things like circular saws and suchlike all set up and poised for action.

You get access to a bunch of tools, plus you can have your own private workspace too. I joined the one here in Birmingham, and it's been a blast (sometimes literally!). I like working on a project while there are people around who have expertise in other disciplines. It's nice being able to get tips from a machininst, a welder, a Linux guru, and a ceramics expert- all without leaving the room!

David -- the master machinist guy mentioned in the blog -- has a friend who has a water jet cutter; that's what was used to cut everything out. Willie -- the guy who created the 3D drawings for me also output the CNC files required to drive the water cutter. They do look tasty, don't they?